13,811 research outputs found

    USSR Space Life Sciences Digest, issue 1

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    The first issue of the bimonthly digest of USSR Space Life Sciences is presented. Abstracts are included for 49 Soviet periodical articles in 19 areas of aerospace medicine and space biology, published in Russian during the first quarter of 1985. Translated introductions and table of contents for nine Russian books on topics related to NASA's life science concerns are presented. Areas covered include: botany, cardiovascular and respiratory systems, cybernetics and biomedical data processing, endocrinology, gastrointestinal system, genetics, group dynamics, habitability and environmental effects, health and medicine, hematology, immunology, life support systems, man machine systems, metabolism, musculoskeletal system, neurophysiology, perception, personnel selection, psychology, radiobiology, reproductive system, and space biology. This issue concentrates on aerospace medicine and space biology

    Arbitrary-speed quantum gates within large ion crystals through minimum control of laser beams

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    We propose a scheme to implement arbitrary-speed quantum entangling gates on two trapped ions immersed in a large linear crystal of ions, with minimal control of laser beams. For gate speeds slower than the oscillation frequencies in the trap, a single appropriately-detuned laser pulse is sufficient for high-fidelity gates. For gate speeds comparable to or faster than the local ion oscillation frequency, we discover a five-pulse protocol that exploits only the local phonon modes. This points to a method for efficiently scaling the ion trap quantum computer without shuttling ions.Comment: 4 page

    Peltier effect in normal metal-insulator-heavy fermion metal junctions

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    A theoretical study has been undertaken of the Peltier effect in normal metal - insulator - heavy fermion metal junctions. The results indicate that, at temperatures below the Kondo temperature, such junctions can be used as electronic microrefrigerators to cool the normal metal electrode and are several times more efficient in cooling than the normal metal - heavy fermion metal junctions.Comment: 3 pages in REVTeX, 2 figures, to be published in Appl. Phys. Lett., April 7, 200

    Diaconates in Transition: Enriching the Roman Catholic Permanent Diaconate from the Experience of the Church of England and British Methodism: A Receptive Ecumenical Approach

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    The Roman Catholic Church, the Church of England and the British Methodist Church have retained or restored the diaconate. These diaconates remain distinctive and capable of further change. This article uses a receptive ecumenical approach to ask what the Roman Catholic Church can learn or receive with integrity from the diaconate in the Church of England and British Methodism. The first section examines the reassessment of the diaconate of service by John N. Collins. The next two sections explore specific learning opportunities from the Church of England Distinctive Diaconate and the British Methodist Diaconal Order. The fourth section examines the way that British Methodism has become alert to the possibilities of unhealthy notions of diaconal service. The final section explores work towards the interchangeability of deacons, concluding that, in the development of the diaconate, the current historical moment provides opportunities for ecclesial learning and perhaps a step towards visible unity

    Catholic Social Teaching Reframed: One Fruit of a Culture of Encounter

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    Catholic social thought and teaching is sometimes conceptualised using an historical or principles-based approach. This paper proposes an alternative framing, construing Catholic social teaching (CST) as a multi-layered phenomenon that can be grouped into three broad tiers, each with a distinctive role. This framing is not intended to supercede the others, nor is it inconsistent with them. The proposal emerges out of a series of discussions hosted by the Catholic Agency for Overseas Development, a Catholic UK-based development agency, member of Caritas Internationalis, and an official agency of the Bishops’ Conference of England and Wales. The paper operates on two levels simultaneously: it attempts a distinctive reframing of CST using a distinctive source, and it attempts an enactment of CST methodologically and structurally. Construing CST as a multi-layered phenomenon that can be grouped into three broad tiers provides a clarity that empowers us in two ways. First, it clarifies the distinctive role of CST at each level. Second, it makes clear that CST is a work of the Spirit rather than a human phenomenon. Such an understanding of CST brings out with particular clarity a vision of the role, purpose, and even the agency of Catholic social thought in relation to a troubled world

    USSR Space Life Sciences Digest, issue 6

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    This is the sixth issue of NASA's USSR Space Life Sciences Digest. It contains abstracts of 54 papers recently published in Russian language periodicals and bound collections and of 10 new Soviet monographs. Selected abstracts are illustrated with figures and tables from the original. Additional features include a table of Soviet EVAs and information about English translations of Soviet materials available to readers. The topics covered in this issue have been identified as relevant to 26 areas of aerospace medicine and space biology. These areas are adaptation, biospherics, body fluids, botany, cardiovascular and respiratory systems, developmental biology, endocrinology, enzymology, exobiology, genetics, habitability and environment effects, health and medical treatment, hematology, human performance, immunology, life support systems, mathematical modeling, metabolism., microbiology, morphology and cytology, musculoskeletal system, neurophysiology, nutrition, perception, personnel selection, psychology, radiobiology, reproductive biology, and space medicine

    Robust quantum gates on neutral atoms with cavity-assisted photon-scattering

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    We propose a scheme to achieve quantum computation with neutral atoms whose interactions are catalyzed by single photons. Conditional quantum gates, including an NN-atom Toffoli gate and nonlocal gates on remote atoms, are obtained through cavity-assisted photon scattering in a manner that is robust to random variation in the atom-photon coupling rate and which does not require localization in the Lamb-Dicke regime. The dominant noise in our scheme is automatically detected for each gate operation, leading to signalled errors which do not preclude efficient quantum computation even if the error probability is close to the unity.Comment: 4 pages, 3 figure

    Control of macrophytes by grass carp (ctenopharyngodon idella) in a Waikato drain, New Zealand

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    Hornwort (Ceratophyllum demersum L.) and other aquatic macrophytes have historically been mechanically removed from the Rangiriri drain and Churchill East drain to maintain drain efficiency. As an alternative control method for the high plant biomass that accumulates at the end of summer, the effect of stocking diploid grass carp (Ctenopharyngodon idella L.) on the aquatic vegetation was evaluated in these Waikato drainage systems. At the start of the trial, both drains had a low diversity of aquatic macrophytes, and of the nine species (including the emergents), seven were exotic. Two months after grass carp were released to Churchill East drain (the treated drain) the four submerged and floating macrophyte species became scarce in the main drain. Over the same period, these species increased in biomass in Rangiriri drain (the untreated drain), where hornwort became dense and surface-reaching and remained so for the duration of the trial. However, grass carp did not control submerged vegetation in smaller side drains or the shallow, upper parts of the main drain, or the marginal sprawling species and emergent species. The cost of leasing the grass carp was similar to the cost of clearing the drains mechanically, but grass carp provided continuous weed control. However, subsequent to this trial, 62 dead grass carp were found in Churchill East drain in February 2001, and weed cover subsequently increased. This illustrates that grass carp management in New Zealand agricultural drains can be problematic due to periodic fish kills

    Revivals of Coherence in Chaotic Atom-Optics Billiards

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    We investigate the coherence properties of thermal atoms confined in optical dipole traps where the underlying classical dynamics is chaotic. A perturbative expression derived for the coherence of the echo scheme of [Andersen et. al., Phys. Rev. Lett. 90, 023001 (2003)] shows it is a function of the survival probability or fidelity of eigenstates of the motion of the atoms in the trap. The echo coherence and the survival probability display "system specific" features, even when the underlying classical dynamics is chaotic. In particular, partial revivals in the echo signal and the survival probability are found for a small shift of the potential. Next, a "semi-classical" expression for the averaged echo signal is presented and used to calculate the echo signal for atoms in a light sheet wedge billiard. Revivals in the echo coherence are found in this system, indicating they may be a generic feature of dipole traps
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